Plotting Matrix Datetime index decade

[PaulMunters]

I have very long dataframes with hourly observations for extended and varying time periods. The y-axis values sometimes become unreadable due to overlapping (see example). I tried in vain many options from the pandas timeframe documentation to set freq, or periods etc.

Is it possible to set a fixed number of Y-axis ticks that are evenly distributed over the axis, say 5 or 10, in combination with freq="Y". Or to use decades instead of year?

[ResidentMario]

The freq feature is generally problematic. It's not powerful enough for what it does, and should either be removed or improved. See #147 (comment) for a previous comment to the same effect.

Until I rewrite this bit of code, you should still be able to do what you want to do by editing the plot directly using matplotlib commands. missingno outputs a matplotlib plot after all.